Doping-Induced Enhancement of Hydrogen Evolution at MoS₂ Electrodes

Area of Science:

• Materials Science
• Computational Chemistry
• Electrochemistry

Background:

• The hydrogen evolution reaction (HER) is crucial for clean energy technologies.
• Molybdenum disulfide (MoS2) is a promising catalyst for HER, but its activity can be tuned by doping.
• Understanding impurity effects on MoS2 is key to optimizing its catalytic performance.

Purpose of the Study:

• To investigate the impact of Co, Ni, and Pt impurities on the hydrogen evolution reaction (HER) on MoS2.
• To elucidate the reaction mechanisms and identify active sites.
• To correlate theoretical calculations with experimental observations.

Main Methods:

• Density Functional Theory (DFT) calculations to model HER on doped MoS2.
• Rate theory to analyze reaction pathways and kinetics.
• Investigation of both edge and basal plane defect sites.

Main Results:

• Doping MoS2 edges with Co, Ni, and Pt significantly reduces the overpotential for HER, especially at 25% substitution.
• Cobalt-doped MoS2 remains highly active at full edge substitution, while Ni and Pt lead to deactivation.
• The basal plane's intrinsic activity originates from undercoordinated Mo atoms in threefold S-vacancy configurations, with impurity interaction leading to deactivation.

Conclusions:

• The stabilization of the dihydrogen (H2*) intermediate is critical for HER activity on doped MoS2.
• Doping concentration and impurity type strongly influence HER performance, explaining experimental variations.
• DFT and rate theory provide valuable insights into designing efficient HER catalysts based on MoS2.